1. Field
Example embodiments relate to color separation devices and image sensors including the same, and more particularly, to color separation devices capable of changing the propagation direction of incident light according to the wavelength of the light and an image sensor having improved light use efficiency due to use of the color separation devices and color filters.
2. Description of the Related Art
Generally, color displays and color image sensors respectively display multicolor images and detect colors of incident light by using color filters. Most of the currently used color displays, or color image sensors, use a RGB color filter format in which, for example, green filters are disposed in two of four pixels and blue and red filters are disposed in the two other pixels. In addition to the RGB color filter format, a CYGM color filter format in which complementary cyan, yellow, green, and magenta color filters are respectively disposed in four pixels is used.
However, because the color filters absorb all colors of light except for a filtered color, the light use efficiency of the color filters may be low. For example, because RGB color filters only transmit about ⅓ of incident light and absorb about ⅔ of the incident light, the light use efficiency of the RGB color filters is only about 33%. Therefore, most of the optical loss of the color displays, or color image sensors, is caused by the color filters.
Recently, attempts to use color separation devices instead of color filters have been made so as to improve the light use efficiency of the color displays, or color image sensors. The color separation devices may separate colors of incident light by using the diffraction or refraction characteristics of light which vary with the wavelength thereof, and colors separated by color separation devices may be provided to corresponding pixels. However, the current color separation devices do not provide clear colors compared to color filters.